Is the PD accuracy the same with and without glasses?

Single PD value is always the same accuracy with or without glasses.

To explore Single PD accuracy : refer to this page

Monocular PD, displaying right and left value, have another processing.

Today monocular PD is slightly different with a common accuracy of 2mm.
Fittingbox is currently improving  the accuracy to provide the same level of accuracy for left and right value.